OBJECTIVE: Melasma is an acquired pigmentary disorder for which tranexamic acid (TA) injection has shown promising results in earlier studies. This study aimed to evaluate the effectiveness and safety of intradermal TA as an adjuvant therapy for melasma in individuals with Fitzpatrick Skin Type IV–V. METHODS: We conducted a double-blind, randomized, split-face controlled trial of 34 female patients with melasma. All subjects were randomized to receive either 10mg of intradermal TA or placebo injection on the right or the left side of their face. The primary outcome was improvement of melasma lesions assessed by modified Melasma Area and Severity Index (mMASI) score and mexameter examination which includes Melanin Index (MI) and Erythema Index (EI). Measurements were done at baseline and every two weeks for 12 weeks. Additionally, side effects of therapy and subject satisfaction assessment with patient global assessment (PtGA) were also documented. RESULTS: This study showed the reduction of mMASI score was larger and faster in intervention group compared to control group whereas the reduction of MI and EI was not significantly different between both groups. The majority of subjects did not experience any serious side effects. The subjects in the treatment group also reported significantly higher proportion of very good response compared to control group. LIMITATIONS: This was a single-center study with a small sample size and the inability to control confounding variables. CONCLUSION: Based on our results, intradermal TA injection appears to be an effective and safe adjuvant therapy for melasma in individuals with Fitzpatrick Skin Type IV–V. © 2025 Matrix Medical Communications. All rights reserved.